Silyl derivatives of 2,6-dimethyl-4-allyl phenol

ABSTRACT

Silyl derivatives of 2,6 dimethyl, 4-allyl phenol include compositions of the formula ##STR1## where R 1 , R 2 , and R 3  are independently selected from alkyl and phenyl groups having up to about eight carbon atoms and/or are connected to form one or more rings. They may be made by silylating the corresponding hydroxyl compound. They are useful as comonomers for olefins to introduce functional sites in high molecular weight copolymers.

This application is a continuation-in-part of pending application Ser.No. 375,644, filed July 5, 1989, now U.S. Pat. No. 4,916,248.

TECHNICAL FIELD

This invention relates to new silyl derivatives of a certain substitutedphenol, specifically to silyl derivatives of 2,6-dimethyl4-allyl phenol.In particular, it relates to compositions of the formula ##STR2##wherein R¹, R² and R³ are independently selected from linear, branchedand cyclic hydrocarbon groups having from one to about eight carbonatoms. R¹, R², and/or R³ may be connected to form one or moresubstituted or unsubstituted rings, and R¹, R², and R³ have a total ofup to 24 carbon atoms.

BACKGROUND ART

In United States patent application Ser. No. 047,960 (see correspondingPCT International Publication No. W088/08856, Nov. 17, 1988), it isdisclosed that comonomers for propylene may be made by protecting theoxygen of a copolymerizable hydroxy-containing compound by substitutingthe hydrogen thereof with a silyl group having at least some stericbulk, i.e., at least about three carbon atoms in separate groupssurrounding it.

Silylated monomers of the general formula ##STR3## are suggested in theabove-referenced publication.

The peculiar advantage, however, of 2,6 dimethyl 4-allyl phenol as apotential comonomer in its silylated form apparently has not been seenin the prior art.

The compound 2,6 dimethyl, 4-allyl phenol is known. See Tarbell, D.Stanley, and Kincaid, John F. JACS, 62, 1940, 728-31.

DISCLOSURE OF INVENTION

The invention herein is a series of new compounds of the formula##STR4## where R¹, R² and R³ are independently selected from linear,branched and cyclic hydrocarbon groups having from one to about eightcarbon atoms; R¹, R², and R³ may connect to form one or more rings,including a total of up to about 24 carbon atoms. They are useful ascomonomers for propylene to insert units having reactive sites into thepolymer chain where highly active Ziegler-Natta catalysts may otherwiseprevent such insertion.

Examples of hetero compounds (such as compounds with heterocyclicsubstituents involving Si) within the above expression are ##STR5## and##STR6##

Following are examples of the preparation of such compounds.

All operations were performed under inert atmosphere using standardSchlenk techniques. All liquid reagents and solvents were purged withinert gas prior to their introduction into the reaction system.

EXAMPLE 1 (2,6-dimethyl-4-allyl) phenoxy diphenylmethyl silane

32.700 g (0.202 mol) of 2,6 dimethyl-4-allyl phenol were added to a 250ml flask with an Argon inlet followed by 0.325 g (0.014 mol) sodium.After one-half hour of stirring, the sodium had completely reacted and45.569 g (0.188 mol) of diphenylmethyl (ethoxy) silane were added tothis mixture. Stirring continued for one hour at which time a refluxcondenser was attached and the solution was heated for 4 hours. Vacuumdistillation at 1 mm Hg and gas chromatographic mass spectral analysisof the resultant collections indicated that none of the desired producthad formed. The first two fractions contained the phenol and these wererecombined in a 250 ml Schlenk flask and 0.2 g sodium were addedfollowed by 50 ml of tetrahydrofuran (which promoted reaction of thesodium). The solution was homogeneous after 1 hour of stirring and thethird fraction (from vacuum distillation), which had been found tocontain the silane, was added to the solution. A reflux condenser wasattached and the mixture was heated for about 6 hours (variac settingswere from 40-70). Some dark precipitate was observed at that time andthe heating was discontinued for fear of decomposition. Vacuumdistillation of this mixture produced three fractions of which thehighest boiling (112°-190° C. at 1 mm Hg) was found to contain thedesired product. The product's identity was confirmed by ¹ H NMR and gaschromatography and the yield was 3.5 g (5%).

EXAMPLE 2 (2,6-dimethyl-4-allyl)phenoxy dimethylethyl silane

12.888 g (0.068 mol) of 2,6-dimethyl-4-allyl phenol were added to a 500ml flask with an Argon inlet and a cool water bath was applied. 1.56 g(0.068 mol) of sodium were cut into small pieces and were added to thiscooled solution. This mixture was allowed to slowly warm to roomtemperature while stirring for four hours. At this time, 30 ml oftetrahydrofuran were added in order to encourage complete reaction ofthe sodium, and stirring was continued overnight.

8.500 g (0.069 mol) of dimethylethyl (chloro) silane were then addeddropwise through an addition funnel. The resultant mixture was stirredfor 5 hours at which time 250 ml of heptane were added and theprecipitate was allowed to settle over the next day. The NaCl wasremoved by filtration of the colloid through filter paper and thenthrough fritted glass/Celite. The product distilled at 120°-122° C. (1mm Hg) with a yield of 5 g (30%).

EXAMPLE 3 (2,6-dimethyl-4-allyl) phenoxy trimethylsilane

65.5 g (0.404 mol) of Argon-saturated 2,6-dimethyl-4-allyl phenol wasadded to a 250 ml round bottom flask with an Argon inlet. To this flaskwas added 31.96 g (0.404 mol) of pyridine followed by 90 ml of pentane.Both of these materials were previously purged with Argon. 43.89 g(0.404 mol) of Argon-saturated chlorotrimethylsilane were then addeddropwise to the stirred solution of the phenol over a period of 45minutes. White precipitate (pyridinium hydrochloride) began to formimmediately. The mixture was allowed to stir at room temperature for sixhours at which time stirring was discontinued in order to let theprecipitate settle out overnight.

The supernatant solution was cannula filtered into a clean 500 mlSchlenk flask. The precipitate was washed three times with 40 mlportions of Argon-saturated pentane and these washings were alsofiltered and added to the bulk solution. The pentane was removed withvacuum (1 mm Hg). The flask was then fitted with a distillation head andthe mixture was distilled at 1 mm Hg. The desired product was collectedat 83°-86° C. in 68% yield (65 g).

A general procedure for copolymerizing our new compounds with ethyleneor propylene follows:

Standard inert atmosphere techniques were used to exclude moisture andoxygen throughout the manipulations recited below.

A round bottom flask fitted with a side arm, magnetic stirring bar and astopper, which apparatus had been assembled hot from a drying oven andwas then either evacuated and refilled with inert gas several times or(and) purged with the inert gas for at least 15 minutes, was chargedwith a given amount of solvent, heptane or toluene, usually 125 ml. Thesolvents were freshly distilled from sodium and triethyl aluminum (TEA)over which they had been refluxing for at least 18 hours under an inertatmosphere. Immediately after the solvent had been charged to the flask,alkyl aluminum co-catalyst, which was in the form of a heptane solutionof about 25 wt% (0.715 g/ml in heptane), was also added to the flaskwhich was then lowered into a thermostated oil bath and magneticstirring was begun.

At this point the inert gas atmosphere in the flask was replaced withthe gaseous comonomer by a minimum of 3 cycles of evacuation andrefilling back to atmospheric pressure with the comonomer. After thethird cycle, the solution was stirred for at least 10 minutes (usuallylonger) to allow the solvent to become saturated with the comonomer.Pressure was maintained at about one atmosphere via a bubbler.

Next were added an "external donor", which usually was diphenyldimethoxy silane or phenyl triethoxy silane, if one was being used, andthe other comonomer. The polymerization was initiated by the addition ofthe transition metal containing co-catalyst, which was a titaniumtetrachloride on a magnesium chloride support.

As the gaseous comonomer was consumed it was replaced by maintaining thepressure constant at one atmosphere via a bubbler.

After a specified period of time (generally about two hours) thereaction was quenched by the addition of acidified alcohol (HCl iniso-propanol, ethanol, and/or methanol). The quenched reaction slurrywas combined with the alcohol solution of volume at least twice theoriginal volume of the inert reaction solvent. The resultant slurry wasstirred for at least 45 minutes and then filtered. This treatment notonly stopped the reaction, it dissolved catalyst residues and removedthe silyl groups and thus regenerated the hydroxyl groups.

If the filtration proceeded very slowly, the slurry was combined withenough water to make the filtration proceed at a convenient rate.

The polymer was resuspended in alcohol, stirred, filtered and vacuumdried overnight. Boiling heptane soluble content was determined bystandard methods.

The utility of our new compounds as comonomers for lower olefins is thusdemonstrated. Functional substitutes such as dyes may be placed on theregenerated hydroxyl groups in the copolymer chain.

EXAMPLE 4 For the copolymerization of propylene and(2,6-dimethyl-4-allyl) phenoxy diphenylmethyl silane, the followingspecific procedure was used:

A 500 ml flask with a sidearm was evacuated and refilled with argonthree times. To this flask were added 75 ml of dry, degassed heptane andthe solvent was saturated with propylene. 3.23 ml of triethylaluminumco-catalyst (0.715 g/ml in heptane) were then added to this solutionfollowed by 3.60 ml (0.010 mol) of (2,6-dimethyl-4allyl) phenoxydiphenylmethyl silane and the flask was placed in an oil bath which hadbeen maintained at 50° C.

The polymerization was initiated by the addition of 0.075 g of titaniumco-catalyst and the mixture was stirred for two hours at which time itwas quenched by the addition of approximately 300 ml of acidifiedisopropanol. The alcoholic solution was allowed to stir for 1.5 hoursprior to filtration of the polymer. Resuspension of the product inisopropanol and stirring for 15 minutes provided the final wash for thepolymer. The product was then filtered and vacuum dried.

We claim:
 1. A compound of the formula ##STR7## in which R¹, R², and R³are independently selected from linear, branched and cyclic hydrocarbongroups having from one to about eight carbon atoms, and at least two ofR¹, R², and R³ are connected to form one or more substituted orunsubstituted rings.
 2. (2,6-dimethyl-4-allyl) phenoxy trimethylsilane.3. Compound of the formula ##STR8## in which R¹ is selected from linear,branched and cyclic hydrocarbon groups having from one to about eightcarbon atoms.
 4. Compound of the formula ##STR9##